1. Field of the Invention
The present invention relates to a field emission display device which can prevent mixing of colors between the phosphor elements of the field emission display device.
2. Description of the Related Art
In general, field emission display devices are used in display panels of electron guns, microwave tubes, ion sources, scanning tunneling microscopes, etc.
In the conventional field emission display device as such, a plurality of cathodes 2 are formed on a lower substrate 1 in a shape of stripes, as shown in FIG. 1. Above each of the cathodes 2 is disposed a gate electrode 3 through which portions of each cathode 2 are exposed. Metal tips 4 are formed on the exposed portions of the cathode 2.
A plurality of anodes 11 are formed in a shape of stripes on an inner surface of an upper substrate 10 which is opposed to the lower substrate 1. The anodes 11 extend making angles with the extending direction of the cathodes 2, for example, the anodes 11 extend in the transverse direction of the cathodes 2 as shown. On the anodes 11 are disposed red, green, and blue (hereinafter, R, G, and B) phosphor elements 12a, 12b, and 12c corresponding to the cathodes 2. Further, black matrices 13 are formed at both sides of the R, G, and B phosphor elements 12a, 12b, and 12c to define the borders between the phosphor elements. In this case, the height of the R, G, and B phosphor elements 12a, 12b, and 12c and the black matrices 13 is about several micrometers. Moreover, a spacer 14 is interposed between the lower substrate 1 and the upper substrate 10, so as to maintain the gap between them.
In the conventional field emission display device having the above mentioned construction, electrons accelerated after being emitted from the metal tips 4 of the cathodes 2 excite the R, G, and B phosphor elements 12a, 12b, and 12c, to thereby generate luminescence.
However, there are the following problems in the conventional field emission display device. That is, the electrons emitted and accelerated from the metal tips 4 of the cathodes 2 not only advance straight forward to excite the corresponding phosphor element 12b, but also advance diverging to excite the adjacent phosphor elements 12a and 12c, thereby generating a crosstalk. Due to this phenomenon, the R, G, and B phosphor elements 12a, 12b, and 12c become simultaneously luminescent to generate a mixing of colors in the field emission display device, thereby deteriorating the screen quality of the device.
Moreover, since the R, G, and B phosphor elements 12a, 12b, and 12c are in a liquid state, it is difficult to pattern the R, G, and B phosphor elements 12a, 12b, and 12c in such a manner as to make them correspond to the cathodes 2.
Further, it is also difficult to form the spacer 14 after forming the phosphor elements 12a, 12b, and 12c, because the phosphor elements 12a, 12b, and 12c are not solid.
In addition, the laterally diverging electrons are charged in the spacers 14, so as to short-circuit the lower substrate 1 and the upper substrate 10, thereby generating a phenomenon of flashover.
Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art, and it is an object of the present invention to provide a field emission display device, in which a phenomenon of crosstalk is prevented, thereby having an improved screen quality.
In accordance with one aspect, the present invention provides a field emission display device comprising:
an upper substrate and a lower substrate spaced apart with a predetermined gap and opposed to each other;
cathode assemblies formed in a shape of stripes on an inner surface of the lower substrate;
anodes formed on an inner surface of the upper substrate;
black matrices formed on the anodes, the black matrices being disposed at locations respectively corresponding to every space between the cathode assemblies, the black matrices respectively having a shape of a partition; and
R, G, and B phosphor elements formed in spaces between the black matrices, the R, G, and B phosphor elements being disposed so as to respectively correspond to the cathode assemblies.
Preferably, the field emission display device may further comprise spacers for maintaining the gap between the upper substrate and the lower substrate, the spacers being respectively formed on inner surfaces of end black matrices which are disposed at both ends among an arrangement of the black matrices. The black matrices respectively have a height of a range between 20 and 300 micrometers.
More preferably, in the field emission display device, each of the cathode assemblies comprises:
a cathode formed in a shape of a stripe on the inner surface of the lower substrate;
a gate electrode formed above the cathode, the gate electrode having a plurality of holes formed through the gate electrode; and
a plurality of metal tips formed on the cathode, the metal tips being exposed through the holes of the gate electrodes. The black matrices are any one of conductor material or insulator material.
In accordance with another aspect, the present invention provides a field emission display device comprising:
an upper substrate and a lower substrate spaced apart with a predetermined gap and opposed to each other;
cathode assemblies formed in a shape of stripes on an inner surface of the lower substrate;
anodes formed on an inner surface of the upper substrate;
black matrices formed from regions between the cathode assemblies on an inner surface of the lower substrate to regions between anodes on the inner surface of the upper substrate; and
R, G, and B phosphor elements formed in spaces between the black matrices, the R, G, and B phosphor elements being disposed so as to respectively correspond to the cathode assemblies.
In this case also, each of the cathode assemblies may comprise:
a cathode formed in a shape of a stripe on the inner surface of the lower substrate;
a gate electrode formed above the cathode, the gate electrode having a plurality of holes formed through the gate electrode; and
a plurality of metal tips formed on the cathode, the metal tips being exposed through the holes of the gate electrodes. However, the black matrices should be necessarily insulating.
In accordance with another aspect, the present invention provides a field emission display device comprising:
an upper substrate and a lower substrate spaced apart with a predetermined gap and opposed to each other;
cathode assemblies formed in a shape of stripes on an inner surface of the lower substrate;
black matrices formed on an inner surface of the upper substrate, the black matrices being disposed at locations respectively corresponding to every space between the cathode assemblies, the black matrices respectively having a shape of a partition;
anodes formed on the inner surface of the upper substrate, the anodes being respectively disposed between the black matrices; and
R, G, and B phosphor elements formed on the anodes, the R, G, and B phosphor elements respectively corresponding to the cathode assemblies.
In this aspect also, the field emission display device may further comprise spacers for maintaining the gap between the upper substrate and the lower substrate, the spacers being respectively formed on inner surfaces of end black matrices which are disposed at both ends among an arrangement of the black matrices.